Add migration notes to READMEs.

- Fix examples.
- Do not link to unrelated example, it's confusing.

Author: greenrobot-team

objectbox-rxjava/README.md

@@ -1,3 +1,6 @@
+:information_source: This library will receive no new features.
+Development will continue with the [RxJava 3 APIs for ObjectBox](/objectbox-rxjava3).
+
 RxJava 2 APIs for ObjectBox
 ===========================
 While ObjectBox has [data observers and reactive extensions](https://docs.objectbox.io/data-observers-and-rx) built-in,
@@ -13,7 +16,7 @@ For general object changes, you can use `RxBoxStore` to create an `Observable`.
 For example to get query results and subscribe to future updates (Object changes will automatically emmit new data):
 
 ```java
-Query query = box.query().build();
+Query<User> query = box.query().build();
 RxQuery.observable(query).subscribe(this);
 ```
 
@@ -27,5 +30,3 @@ implementation "io.objectbox:objectbox-rxjava:$objectboxVersion"
 Links
 -----
 [Data Observers and Rx Documentation](https://docs.objectbox.io/data-observers-and-rx)
-
-[Note App example](https://github.com/objectbox/objectbox-examples/blob/master/objectbox-example/src/main/java/io/objectbox/example/ReactiveNoteActivity.java)

objectbox-rxjava3/README.md

@@ -13,7 +13,7 @@ For general object changes, you can use `RxBoxStore` to create an `Observable`.
 For example to get query results and subscribe to future updates (Object changes will automatically emmit new data):
 
 ```java
-Query query = box.query().build();
+Query<User> query = box.query().build();
 RxQuery.observable(query).subscribe(this);
 ```
 
@@ -24,8 +24,16 @@ Grab via Gradle:
 implementation "io.objectbox:objectbox-rxjava3:$objectboxVersion"
 ```
 
+Migrating from RxJava 2
+-----------------------
+
+If you have previously used the ObjectBox RxJava library note the following changes:
+
+- The location of the dependency has changed to `objectbox-rxjava3` (see above).
+- The package name has changed to `io.objectbox.rx3` (from `io.objectbox.rx`).
+
+This should allow using both versions side-by-side while you migrate your code to RxJava 3.
+
 Links
 -----
 [Data Observers and Rx Documentation](https://docs.objectbox.io/data-observers-and-rx)
-
-[Note App example](https://github.com/objectbox/objectbox-examples/blob/master/objectbox-example/src/main/java/io/objectbox/example/ReactiveNoteActivity.java)